Z-Scheme CuOx/Ag/TiO2 Heterojunction as Promising Photoinduced Anticorrosion and Antifouling Integrated Coating in Seawater

Abstract

In the marine environment, steel materials usually encounter serious problems with chemical or electrochemical corrosion and fouling by proteins, bacteria, and other marine organisms. In this work, a green bifunctional Z-scheme CuOx/Ag/P25 heterostructure coating material was designed to achieve the coordination of corrosion prevention and antifouling by matching the redox potential of the reactive oxygen species and the corrosion potential of 304SS. When CuOx/Ag/P25 heterostructure was coupled with the protected metal, the open circuit potential under illumination negatively shifted about 240 mV (vs. Ag/AgCl) and the photoinduced current density reached 16.6 μA cm−2. At the same time, more reactive oxygen species were produced by the Z-shape structure, and then the photocatalytic sterilization effect was stronger. Combined with the chemical sterilization of Ag and the oxide of Cu, the bacterial survival rate of CuOx/Ag/P25 was low (0.006%) compared with the blank sample. This design provides a strategy for developing green dual-functional coating materials with photoelectrochemical anticorrosion and antifouling properties.

Facile Solution‐Processed Semiconductor/Metal Hybrid Nanoporous Materials; their Highly Photoredox Catalytic Power

“…As depicted in Figure 5a, adding BQ, a superoxide radical ( • O 2 − ), a singlet oxygen ( 1 O 2 ) scavenger, [48] almost completely terminates the photocatalytic reaction of 4-NP degradation. A similar and apparent inhibition phenomenon for photocatalysts is observed when IPA, a hydroxyl radical (•OH) scavenger, EDTA, a hole radical (h + ), sodium azide (SA) (NaN 3 ) as singlet oxygen ( 1 O 2 ) scavenger [36,49] are added, indicating that h + , •OH,…”

“…As depicted in Figure a, adding BQ, a superoxide radical ( · O 2 − ), a singlet oxygen ( 1 O 2 ) scavenger, [ 48 ] almost completely terminates the photocatalytic reaction of 4‐NP degradation. A similar and apparent inhibition phenomenon for photocatalysts is observed when IPA, a hydroxyl radical (·OH) scavenger, EDTA, a hole radical (h + ), sodium azide (SA) (NaN 3 ) as singlet oxygen ( 1 O 2 ) scavenger [ 36,49 ] are added, indicating that h + , ·OH, 1 O 2 , and · O 2 − radicals all have a significant impact on the degradation of 4‐NP. However, compared to BQ, SA, and IPA, adding EDTA results in less photoactivity inhibition, indicating that · O 2 − , 1 O 2, and ·OH radicals are more significant than other reactive species in the photodegradation of 4‐NP over CuO‐Ag nanoporous structure.…”

“…[34] After adding Ag nanoporous material, the apparent photocurrent density over the CuO-Ag structure confirms the significant photosensitization effect of Ag on the photocurrent performance in the visible light range. [35,36] The greater photocurrent enables charge migration at the junction between Ag and CuO by preventing charge recombination. Furthermore, electrochemical impedance spectroscopy (EIS) curves (Figure 4g) show that the Nyquist plot of CuO-Ag nanoporous structure exhibited semicircle signatures more than that of porous Ag and CuO, which is comparable with the reported literatures.…”

Review of TiO2-Based Heterojunction Coatings in Photocathodic Protection

“…This charge migration method enables the effective separation of e − −h + . 131 Therefore, the construction of Z-scheme heterojunctions represents an ideal approach for enhancing the photoelectrochemical performance of TiO 2 . Generally, Z-scheme heterojunction coatings include all-solid-state Z-scheme heterojunctions and direct Z-scheme heterojunctions.…”

Adhesive and Rheological Features of Ecofriendly Coatings with Antifouling Properties

“…Among the allowed materials, nanocomposites based on Cu/TiO2 and Ag/TiO2 oxides have been already studied for their antifouling properties, namely their ability of a surface to resist the adhesion and growth of marine organisms, such as algae, barnacles, and mussels, which can affect the performance of marine structures, ships, and underwater pipelines [22][23][24][25][26].…”